JP3531889B2 - Swing type plasma torch - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma torch used for welding, cutting, punching, heating and the like.

[0002]

2. Description of the Related Art Welding by a plasma arc is performed when performing corner-less welding such as fillet welding.
This is because plasma arc welding has good arc heat concentration and good directivity, so that arc heat can be radiated to the ridges of the corners without arc fluctuations and fusion welding can be performed. However, depending on the shape of the members to be welded, the joints may not be in close contact with each other, and welding with a large welding material gap may be performed using a plasma arc having a tight shape.
FIG. 6 shows these examples. FIG. 6A shows a steel plate W2 which is parallel to the base steel plate W2 with a gap (gap d).
1 is a mode in which the edge of No. 1 is overlapped with a plasma torch T and fillet welded, (b) is a mode in which pipes W3 and W4 are welded to each other on the peripheral surface, and (c) is a corner of the sheet metal case W6. It is a mode in which the flat surface of the component W5 is welded to a press-bending portion such as a portion, and (d) shows an end portion of the plate-shaped material to be welded W7 like a plate joint at the time of welding an automobile outer plate, This is a mode in which welding is performed so as to fill the stepped portion of the steel plate that receives it. In the plasma arc welding that performs these, the heat concentration of the arc is good, but the proper leg length is short at a maximum of 3 to 4 mm.
When welding with a large welding gap or a large leg length as shown in (d) is performed, there is a possibility that a problem such as a weld bead not bridging occurs. Also in the fillet welding, if the welding with a large leg length is performed, for example, in (c) of FIG. 6, the molten metal of the vertically arranged component W5 falls downward due to gravity and becomes an unbalanced bead. Problems such as undercutting may occur in the part W5. Furthermore, if the torch is slightly displaced from the target position, problems such as non-uniform beads, undercuts, and no bridging occur, so highly accurate copying is required, and a highly accurate copying mechanism is used. And the welding equipment is complicated and expensive. When the copying is manually performed by the worker, the work efficiency is reduced.

In order to solve these problems, Japanese Unexamined Patent Publication (Kokai) 2
In Japanese Patent Laid-Open No. -210799, a method is proposed in which the flow velocity of the plasma gas in the axial direction is suppressed and the arc is rotated at a high speed by utilizing the deforming force due to the instability of the plasma's Kink. Further, according to Japanese Patent Laid-Open No. 4-178282, a plurality of electrodes are provided in a torch, an AC voltage is supplied from an AC power supply, a plasma arc is rotated by a magnetic generator, and a base material is irradiated and heated over a wide range. It shows how to do it. According to this, plasma welding with a wide leg length is realized.

[0004]

However, Japanese Patent Laid-Open No. 2-2
In the method disclosed in Japanese Patent No. 10799, since kink instability is used, it is difficult to obtain a quantitative rotation speed, rotation angle, and uniform heat distribution. That is, it is difficult to obtain a uniform bead. In addition, JP-A-4-178282
In the method disclosed in the publication, a plurality of electrodes are required and a magnetic field generator for rotation driving is required, and the apparatus is large and requires a large work space. Also, the device is complicated and expensive.

An object of the present invention is to quantitatively widen the working area of the arc even though the heat concentration of the arc is high.

[0006]

The swing plasma torch of the present invention comprises a discharge electrode (1); a work directing line of the discharge electrode (1).
A nozzle member (2) having a nozzle (2a) whose outer opening is displaced (θ) with respect to (Lo); a gas flow path for supplying a plasma gas to the inner space of the nozzle member (2); A drive means ((M, mr, 32, 33, 37) for rotating the nozzle member (2) about the work line (Lo) substantially as a center is provided. In parentheses, the symbols of the corresponding elements in the examples shown in the drawings and described later are added for reference.

According to this, the drive means (M, mr, 32, 33, 37)
As the nozzle member (2) is driven to rotate, the nozzle (2a)
Since the outer opening of the nozzle is deviated (θ) with respect to the work directing line (Lo), the center line of the nozzle (2a) is rotated so as to draw a conical surface, and the nozzle (2a) is rotated. The plasma that comes out also rotates so as to draw a conical surface. Since the plasma hits the material to be processed on the lower bottom side of the cone, the plasma action region is wide with respect to the material to be processed in terms of time series average. Therefore,
Even if the target position of J is slightly displaced, the plasma arc acts on the intended position. In welding, copying accuracy may be low, and welding with a long leg length and welding with a large gap at the mating portion is possible. The inner opening of the nozzle (2a) is preferably substantially aligned with the work directing line (Lo), but may be slightly deviated from the work directing line (Lo).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the first aspect, the drive means (M, mr, 3
2, 33, 37) is a constant-direction continuous rotation drive mechanism (Fig. 1, Fig. 1) including an electric motor (M), and in the second mode, an alternate reversal drive mechanism including an electric motor (M). (FIG. 7). Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0009]

【Example】

-First Embodiment- Fig. 1 shows a welding torch T according to a first embodiment of the present invention. Hereinafter, in each of the drawings, the z direction is the upper side, the y direction is the right side, and the direction x perpendicular to the yz plane (the direction from the back of the paper to the front in FIG. 1) is the welding direction of the welding torch T. FIG. 1 shows a mode in which fillet welding is performed.

A horizontal metal flat plate Wy is placed horizontally on a ground foundation (not shown) horizontal to the xy plane.
A vertical metal flat plate Wz is erected vertically on and parallel to the x-axis. These two metal flat plates W
With respect to y and Wz, an operator who supports the welding torch T welds both contact points (intersection lines) O in the x direction.

In this embodiment, the tungsten rod (welding electrode) 1 is a straight rod body, and the tip of the rod is a line for aiming at the workpiece (work), that is, the work directing line Lo is the tungsten rod 1. Aligns with the centerline of. The worker determines that the work line Lo, which is also the center line of the tungsten rod 1, is the tangent line O.
The welding torch T is tilted and supported, aiming to intersect.
Hereinafter, the horizontal metal flat plate Wy is referred to as a horizontal plate Wy, the vertical metal flat plate Wz is referred to as a vertical plate Wy, and the tangent line O is also referred to as a target position. The horizontal plate Wy and the vertical plate Wy are SM400A made of the same material in this embodiment.

The base B of the welding torch T is a hollow, substantially cylindrical member having an arm attached to the outer peripheral surface thereof. Base B
A flow path for shield gas, (cooling) water, and pilot gas (gas for plasma) is formed inside the arm portion of the above, and communicates with the inner peripheral surface of the substrate B. The water channel sends water from the outside to the inside of the base B, circulates it inside the welding torch T through the insulating water channel 20a, and discharges it again to the outside (shown by a solid arrow in FIG. 1). Gas is fed into the welding torch T from the outside (indicated by a dotted arrow in FIG. 1). Further, the pilot gas flow path sends pilot gas from the outside into the inside of the welding torch T (shown by a two-dot chain line arrow in FIG. 1).

Hereinafter, assuming that the direction of the welding torch T toward the nozzle 2 is the tip direction and the opposite direction is the tail end direction, the base end of the base B has a substantially cylindrical electrode base having a smaller diameter than the base B. 8 is inserted and is integrally fixed to the inner peripheral surface of the base body B. A ring-shaped groove having the same axial center is engraved on the peripheral surface of the tip of the electrode base 8 to form a water channel with the wall of the inner peripheral surface of the base B. The water channel communicates with the water channel inside the arm portion of the base body B. Inside the cylindrical tail end portion of the electrode base 8 protruding from the base B, a chuck 9 whose tip is divided into four in the circumferential direction by slitting is formed.
Is inserted and screwed. The chuck 9 is
The tungsten rod 1 whose tip extending along the center line Lo projects in a conical shape is held. The rear end portion of the electrode base 8 enters into the guide ring 10 and is screwed to the guide ring 10.
Is covered with a cover C. Guide C of cover C 10
The tail end of the chuck 9 is pressed against the inner wall surface (tapered surface) of the cone inside the tail end of the electrode base 8 by screwing into the electrode base 8 and bent in the direction toward the axial center of the tungsten rod 1. The tungsten rod 1 is strongly pressed to reach the target.
As a result, the tungsten rod 1 is integrally fixed to the electrode base 8. That is, since the electrode base 8 is integral with the base B, the tungsten rod 1 is integral with the base B.

On the other hand, in the cylindrical inner space of the base body B, the insulating spacer 7 fixed to the tail end of the substantially cylindrical supporting member Ua.
Therefore, the tail end of the insulating spacer 7 is received while being fixed to the tip of the electrode base 8. The support member Ua is molded and fixed from the intermediate portion of the base B to the tip thereof. The tip surfaces of the base B and the support member Ua are flush with each other, the screw ring 5 having the shield gas injection port 5a is fixed, and the shield cap 6 is screwed to the male screw on the outer periphery of the tip of the screw ring 5. There is. That is, the base B and the support member U
a, the screw ring 5 and the shield cap 6 are all integrated.

The support member Ua and the screw ring 5 are arranged so that the hollow tubular rotary water channel fitting 20b can freely rotate about its axis, that is, the center line Lo, through an O-ring and a bearing b2 in its inner space. To support. The shield gas sent into the shield gas flow path of the base B is sent into the space formed by the inner wall of the screw ring 5 and the outer wall of the metal fitting 20b, passes through the shield gas injection port 5a of the screw ring 5, and comes out to the shield cap 6. From the opening of the tip of the shield cap 6 to the outer space of the tip (nozzle member) 2. The metal fitting 20b is fixed in the z direction while being held in a rotatable state by a stop ring b3, and its tip portion projects into the inner space of the shield cap 6. Metal fittings 2
The tail end of 0b reaches and stops at the groove communicating with the water channel of the base body B provided in the inner wall of the support member Ua in a ring shape. The inner wall reaching the above-mentioned groove from the tail end of the support member Ua is based on the center line Lo, like the metal fitting 20b, with the hollow cylindrical nozzle base 3 having a smaller diameter than the metal fitting 20b via the O-ring and the bearing b1. It is supported so that it can be freely rotated. The inner wall of the metal fitting 20b and the outer wall of the nozzle base 3 form a water passage that communicates with the water passage of the base B through a groove formed in the inner wall of the support member Ua in a ring shape.

At the tip of the rotary water channel fitting 20b, a hollow, substantially conical metal tip 2 is attached so as to surround the tip of a tungsten rod 1 protruding in a cone. There is a nozzle 2a in the central portion of the tip 2 having a conical shape that follows the conical shape of the tip of the tungsten rod 1. The inner opening of the nozzle 2a facing the tip of the tungsten rod 1 is at the center of the tip 2 (center line = position of work direction line Lo), but the nozzle 2a forms an angle of θ with respect to the center line Lo. None, the outer opening of the nozzle 2a facing the work (the intersection line 0 thereof) is the center line, that is, the work directing line L.
deviated from o. The tip 2 is fixed to the tip of the nozzle base 3 via an O-ring, and the outer peripheral edge of the groove is fixed to the tip of the nozzle base 3 to the tip of the metal fitting 20b via the O-ring. That is, the metal fitting 20b, the nozzle base 3, and the tip 2 are integrally fixed, and the support member Ua
Also, it is rotatably supported by the base B via the screw ring 5.

A toothed pulley 37 is fixed to the tail end of the nozzle base 3. The toothed pulley 32 is coupled to the timing belt 33 coupled to the toothed pulley 37. The toothed pulley 32 is fixed to the rotating shaft ma of the electric motor M. Therefore, when the electric motor M rotates, the nozzle base 3
Rotates. When the nozzle base 3 rotates, the metal fitting 20b, the nozzle base 3 and the tip 2 are integrally integrated with the center line Lo.
Rotate around. Inner wall of metal fitting 20b and nozzle base 3
The water channel formed by the outer wall of is closed by a groove formed in the tip 2. The water (cooling water) flowing in from the water channel of the base B passes through the water channel to the insulating water channel 20a of the base B, and is formed between the electrode base 8 communicating with it and the wall of the inner peripheral surface of the base B. The water is discharged to the external cooling water circulation mechanism (not shown) through a water channel different from the above-mentioned water channel of the base B through the water channel.

A ring-shaped centering stone 4 is fixed to the inner wall of the nozzle base 3. The tungsten rod 1 rotatably passes through the center of the centering stone 4, and the axis thereof substantially coincides with the central axes of the tip 2 and the nozzle base 3, that is, the center line Lo. The centering stone 4 is provided with a vent hole which communicates with the inner end of the nozzle 2a from the front end surface to the rear end surface on the back side thereof. The pilot gas sent into the pilot gas flow path of the substrate B is the inner wall of the nozzle base 3 and the tungsten rod 1.
Is discharged into the inner space of the tip 2 through the ventilation hole of the centering stone 4, and is discharged from the nozzle 2a of the tip 2 to the outer space. Since the centering stone 4 is fixed to the nozzle base 3,
When the nozzle base 3 rotates, it rotates together with the metal fitting 20b, the nozzle base 3 and the tip 2 as well as the center line Lo. On the other hand, however, the tungsten rod 1 is fixed to the base B by the chuck 9 via the electrode base 8. That is, it does not rotate.

A major structural difference from the plasma welding torches that have been conventionally used in the above description is that the tip 2 is connected to the base B through the metal fitting 20b and the nozzle base 3.
It is also rotatably supported by the tungsten rod 1. In the conventional plasma torch, the tip 2
Was fixed to the base B. As a usage mode, first, a high frequency voltage is applied between the tip 2 (nozzle member) 2 and the tungsten rod 1 to generate a pilot arc. Next, a main voltage is generally applied between the tungsten rod 1 and the material to be welded to transfer the pilot arc to the material to be welded to generate the main arc. The welding torch T of the present embodiment is provided with a mechanism for rotating the tip 2 in addition to the above-mentioned mechanism. As a result, although the method of generating the main arc is the same as the conventional method, the generated main arc is generated by rotating the tip 2 of the nozzle 2a.
Rotate to draw a cone similar to that drawn by. A description will be given below with reference to the drawings.

FIG. 2 shows a cross section taken along line 2A-2A of FIG.
A substantially box-shaped support member 30 is vertically fixed to the outer periphery of the base B of the welding torch T, and an electric motor M is supported on the outer wall of the support member 30 in parallel with the center line Lo. The rotation axis ma of the motor M projects in the front end direction parallel to the center line Lo. A drive pulley 32 is fixed to the rotary shaft ma. A timing belt 33 is attached to the pulley 32, and the timing belt 33 is wound around a toothed pulley 37 fixed to the tail end of the nozzle base 3. On the inner wall of the support member 30, there is a guide groove 30a perpendicular to the rotation direction of the timing belt 33. A U-shaped slider 36, on which a bearing 34 as a belt pressing roller is mounted, is guided in the guide groove 30a.
By tightening 5, the position in the guide groove 30a is fixed. The timing belt 33 is pressed by the bearing 34 with its outer periphery directed inward. By loosening the bolt 35 and moving the position of the slider 36 along the guide groove 30a, the degree of pressing of the timing belt 33 by the bearing 34 is changed. be able to.

Consider, for example, the case where the rotation shaft ma of the motor M rotates in the direction shown by the solid arrow mr in FIGS. When the rotary shaft ma and the pulley 32 fixed to the rotary shaft ma rotate in the direction of the solid arrow mr, the timing belt 3
The pulley 37 and the nozzle base 3 to which the pulley 37 is fixed are rotated in a direction indicated by a solid arrow mr through the pulley 3. Then, the tip 2 and the rotating water channel fitting 20b, which are integrated with it, similarly rotate.

FIG. 3 (a) is an enlarged vertical sectional view of the tip portion of the welding torch T, and FIG. 3 (b) shows the tip portion of the tip 2 of the torch T from the work side by the one-dot chain line arrow 3B. It is the figure seen from the direction shown by. As described above, the nozzle 2a provided at the tip of the tip 2 has its center line (hole center line) inclined by θ with respect to the work directing line Lo (= the center line Lo of the tungsten rod 1). ing. When the tip 2 rotates in the direction indicated by the solid arrow mr, the tip 2 moves to 1
When the rotation time is divided into four times as a unit time, a certain time point (: solid circle 2a) is used as a reference, and each time the unit time elapses, the position of the nozzle 2a at that moment is set as (b). Is indicated by a dotted circle. That is, the outer opening of the nozzle 2a rotates in a circle centered on the center line Lo.

Next, a mode of fillet welding according to this embodiment will be described. Now refer again to FIG. The positive electrode of the pilot power source Vp is connected to the water channel communicating with the rotating water channel fitting 20b of the base B, and the negative electrode of the pilot power source Vp is connected to the water channel communicating with the electrode base 8 through a transformer for high frequency coupling. There is. The negative electrode of the main power source Vs is connected to the electrode base 8, and the positive electrode of the main power source Vs is the vertical plate Wz.
Alternatively, the horizontal plate Wy (in the present embodiment, the horizontal plate Wy)
It is connected to the. When a high frequency voltage is applied by the high frequency power source Vh while the pilot voltage is applied by the pilot power source Vp, a pilot arc is generated between the tungsten rod 1 and the tip 2. After the pilot arc is generated, the high frequency voltage is stopped. Further, when a main voltage is applied from the main power source Vs in the state where the pilot arc is generated, the tungsten rod 1 and the horizontal plate Wy (horizontal plate Wy in this embodiment) to which the negative electrode of the main power source Vs is connected are connected. The main arc is generated during.

After the main arc is generated, the operator gives a normal rotation or reverse rotation energization command to the motor M as required, and the motor M follows the normal rotation or reverse rotation. In this embodiment, an energization command is given so that the output shaft ma of the motor M rotates in the direction indicated by the solid arrow mr in FIGS. 1, 2 and 3 and FIG. The case will be described.

FIG. 4A is a perspective view showing a vertical cross-sectional view of the tip 2 when the nozzle 2a is at the position shown in FIG. 3, and FIG. 4B is the plasma emitted from the nozzle 2a. FIG. 6 is a perspective view showing a position (welding position) where the contact with the work.
With the rotation of the tip 2, the welding position changes as shown in (b) of FIG. 3 →→→, and the plasma ejected from the nozzle 2a is centered on the tangent line O as shown in (b) of FIG. As it draws a spiral, it moves on the vertical plate Wz and the horizontal plate Wy. That is, the vertical plate Wz and the horizontal plate Wy are welded along the intersection line O.

FIG. 5 shows changes in the actual welding position with respect to the target position O when the direction of the nozzle 2a changes with the rotation of the tip 2, and is shown in correspondence with (b) of FIG. Where (a) corresponds to and (b) corresponds to
And (c) corresponds to. As a result, it can be seen that the plasma is widely swung around the target position O. In this state, a welding wire is supplied from the welding advancing direction shown in FIG.

According to the first embodiment described above, the tip 2
The plasma arc radiated as the gas ejection port 2a of No. 2 rotates about the center line Lo forms a bead having a long leg centered at the target position O. That is, the material to be welded having a large welding gap as shown in FIG. 6 can be welded using the plasma torch. Then, since the molten metal is constantly pushed up to the vertical plate Wz side by the arc force of the plasma arc, the metal is always supplied to the vertical plate Wz side, and the beads have the same leg length. Since the rotation speed of the tip 2 is constant as in the rotation of the electric motor M, the arc is not concentrated at one point, and the rotating force of the arc makes the molten pool agitated and smooth, so that the surface is flat and uneven. A stable bead can be obtained.

Further, since the range of the target of the plasma arc is widened by using the rotating flow, the torch T can be bridged even if the target of the torch T is slightly deviated from the target position O, and a highly accurate and expensive copying is not required. Since the long bead can be formed at a high speed, the range of application of the plasma torch to the type of material to be welded is widened and the work efficiency is increased.

-Second Embodiment- FIG. 7 shows a cross section of a second embodiment corresponding to FIG. 2 of the first embodiment. In this embodiment, the rotating shaft ma of the electric motor M is used.
In addition, one round of spur tooth G1 and slightly less than half round of fan tooth spur tooth G
A drive gear 32A having two upper and lower two (direction in which the rotation axis ma extends) is fixed. In this drive gear 32A,
The spur teeth G2 for one round of the driven gear 32B mesh with each other. Since the spur teeth G1 and G2 have the same radius and the same number of teeth, the driven gear 32B rotates at the same speed but in the opposite direction with respect to the drive gear 32A. The driven gear 32B also has the spur gear G2.
And the fan-shaped spur tooth G4, which is slightly less than half the circumference, is moved up and down (rotation axis m
(direction in which a extends) has two stages. Fan-shaped flat teeth G4 and G3
Have the same radius and the same number of teeth. Toothed drive pulley 32C
In the second embodiment, the fan gears G3 and G4 have one round of spur gears G5 meshing with both of them, but the drive gears 32A and 32B have one fan-shaped spur gear (G4) having a toothed drive tooth.
When meshing with the spur tooth G5 of the groove 32C, the other fan-shaped spur tooth (G3) is set so as not to mesh with the spur tooth G5.
They mesh with an angle difference of 80 degrees. The other structure is the same as that of the first embodiment described above. According to the second embodiment, the rotation of the electric motor M causes the driven gear 32A to rotate counterclockwise when the drive gear 32A rotates clockwise as shown in FIG. In the state shown in FIG. 7, the fan-shaped spur tooth G4 of the driven gear 32B is driven by the toothed drive gear.
Since it meshes with the flat tooth G5 of the pulley 32C, the pulley 32
C rotates clockwise, and the nozzle base 3 (nozzle 2) rotates clockwise. Due to this rotation, when the fan-shaped spur tooth G4 of the driven gear 32B is disengaged from the spur tooth G5 of the toothed drive pulley 32C, this time the fan-shaped spur tooth G3 of the drive gear 32A is sprung G5 of the toothed drive pulley 32C. , The pulley 32C rotates counterclockwise, and the nozzle base 3 (tip 2) rotates counterclockwise.

Thus, for example, if the rotation speed ratio of the pulley 37 to the drive gear 32A is 1, the drive gear 32
While A rotates once, the pulley 37 (chip 2) makes one reciprocating rotation (clockwise half rotation and counterclockwise half rotation) within a range of approximately half rotation. When the center of the reciprocating rotation range is aligned with the tangent line 0 and the plasma fluctuation due to the rotation is distributed substantially evenly to the horizontal plate Wy and the vertical plate Wx, so-called weaving welding is performed with the tangent line 0 as the center.

When the rotation speed ratio of the pulley 37 to the drive gear 32A is smaller than 1, the rotation range of the tip 2 is 180.
If the rotation speed ratio of the pulley 37 to the drive gear 32A is greater than 1, the rotation range of the tip 2 is 180 degrees.
Greater than degree. That is, from the drive gear 32A to the pulley 3
The rotation range of the tip 2 is determined by the speed transmission ratio of the rotation transmission mechanism up to 7. That is, by the rotation transmission mechanism,
It is possible to set the swing width in the direction in which the tangent line 0 extends and in the direction orthogonal thereto. The teeth G3, G4, G5 are not
It may be a rough surface.

The alternating inversion within the predetermined angle range as in the second embodiment can be realized by repeatedly inversion driving the electric motor M. Specifically, referring to FIG. 1, for example,
The electric motor M is provided with a rotary encoder, or the timing belt 33 is provided with a timing mark, and a photo sensor for detecting this mark is provided so that the toothed pulley 32 is predetermined. The electric motor M is driven in the forward direction / reverse direction for each rotation of the angle. This is also within the scope of the present invention, but in this modified example, the rotor of the electric motor M becomes an inertial load, and there is a disadvantage in the case of reversal driving, especially at high speed. In the above-mentioned second embodiment, since the toothed pulley 32C or less makes the reversing motion, and the electric motor M and the gears 32A, 32B are in the constant direction continuous rotation, it is advantageous for the relatively high speed reversing drive. Is.

The following Table 1 shows welding results according to the examples of the present invention (test No. having a circled number) and welding results of comparative examples (conventional example) (test No. having no circle). Show.

[0034]

[Table 1]

The welding conditions are as follows.

* Welding material SM400A Plate thickness 6t * Welding wire YM-28S φ1.2 * Common conditions Shield gas 10 liters / min (Ar) Pilot gas Notation (Ar + 7% H ₂ ) Tungsten rod 2% Tungsten φ3.2 Torch advance angle 5 ° Torch inclination angle 45 ° * Example Nozzle hole outer opening shift amount 0.67 mm Angle θ 15 ° Test No. 1 in Table 1 No. 1 is the result of the conventional fillet welding (without rotation). Although No. 2 is an example of long leg extension, it is a deformed bead having a convex shape on the lower plate side, which is not so good in shape. (No rotation) Test No. No. 3 is No. This is an example of a rotating arc under conditions close to 2, and a smooth bead shape was obtained.

Test No. 4 has a large leg length of 5.1 mm
Under the above conditions, the long leg could be lengthened by using the rotating arc.

Test No. Nos. 5 and 6 are tests for aiming at the center by the conventional method. At -0.5 mm (shifting the target point O of the torch to 0.5 mm to the horizontal plate Wy side), welding with bridging while unequal-sided beads I made it, but -1.0
In mm, welding failure without bridging occurred.

Test No. Nos. 7 and 8 are the test results of aiming toward the center with a rotating arc. At -1.0 mm,
Welded with bridges while unequal beads,-
At 1.5 mm, welding failure without bridging occurred, but it can be seen that the rotating arc has a larger allowance for any change in the target.

Test No. 9 is 3 in the conventional method.
When it was set to about 5 cm / min, the condition range became very narrow, and pits appeared in the middle of the bead and it was easy to find defective points that did not bridge due to defective fusion.

Test No. In Nos. 10 to 11, in the rotating arc, the vertical plate and the lower plate can be sufficiently melted even if the welding speed is increased as compared with the conventional method, so that no fusion failure such as bridge does not occur.

In the conventional method, the molten pool is likely to adhere to the lower plate side due to gravity, and tends to be a downward convex bead. When the embodiment of the present invention is used for the fillet, the supplied wire is melted in the portion (a) of FIG. 4 and the molten metal is constantly pushed up to the vertical plate side by the arc force of the plasma arc. Therefore, since the metal is always supplied to the vertical plate side, there is an effect that the bead shape becomes a bead shape having a substantially equal leg length.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a welding torch T according to a first embodiment of the present invention.

2 is a cross-sectional view (cross-sectional view taken along line 2A-2A in FIG. 1) of the welding torch T shown in FIG.

3 (a) is an enlarged vertical cross-sectional view of the tip portion of the welding torch T shown in FIG. 1, and FIG. 3 (b) shows the tip portion of the tip 2 of the torch T by the alternate long and short dash line arrow in FIG. It is the top view seen in 3B.

4A is a perspective view showing a vertical cross section of the tip 2 when the nozzle 2a shown in FIG. 1 is in the position shown in FIG. 3, and FIG. It is a perspective view which shows the welding position on the vertical board Wz and the horizontal board Wy.

5 (a) is a vertical cross-sectional view showing the direction of plasma ejected from the nozzle of the tip 2 when the position of the nozzle 2a shown in FIG. 1 is at the position shown in FIG. 3 (b),
In (b), the position of the nozzle 2a is shown in (b) of FIG.
3B is a vertical cross-sectional view when the nozzle 2a is in the position shown in FIG. 3B.

FIG. 6A is a transverse cross-sectional view showing a gap d of a welded portion of plate-shaped workpieces W1 and W2 arranged with a gap in the vertical direction, and FIG. It is a transverse cross-sectional view showing the gap d of the welded parts of the pipe-shaped workpieces arranged side by side, (c) is a vertically standing workpiece W5
FIG. 6 is a transverse cross-sectional view showing a gap d of a welded portion due to a corner of the surface of the welded material W6 bent at 90 degrees,
(D) is a transverse cross-sectional view showing the gap d between the end of the plate-shaped material to be welded W7 and the welded portion due to the step portion of the material to be welded having a step on the surface.

FIG. 7 is a cross-sectional view of the main part of the second embodiment of the present invention.

[Explanation of symbols]

1: Tungsten bar 2: Tip 2a: Nozzle 3: Nozzle base 4: Centering stone 5: Screw ring 5a: Shield gas injection port 6: Shield cap 7: Insulating spacer 8: Electrode base 9: Chuck 10: Guide ring 20a: Insulation water channel 20B: Rotating water channel fitting 30a: Guide groove 30, 31: Support members 32, 37: Pulley 33: Timing belt 34: Bearing 35: Bolt 36: Slider B: Base body b2, b1: Bearing b3: Stop ring C: Cover Lo: Reference line M: Motor ma: Rotation axis O: Contact point (target position) T: Welding torch Ua: Support member Vh: High frequency power supply Vp: Pilot power supply Vs: Main power supply Wy: Horizontal metal flat plate (horizontal plate) Wz: Vertical metal plate (vertical plate)

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 10/00 H05H 1/26

Claims (3)

(57) [Claims] 1. A discharge electrode; a nozzle member having a nozzle whose outer opening is displaced with respect to a work directing line of the discharge electrode; a gas flow path for supplying a plasma gas to an inner space of the nozzle member; An oscillating plasma torch comprising: driving means for rotating the nozzle member substantially with the work directing line as a center. 2. The oscillating plasma torch according to claim 1, wherein the drive means is a constant direction continuous rotation drive mechanism including an electric motor. 3. The oscillating plasma torch according to claim 1, wherein said driving means is an alternate reversal driving mechanism including an electric motor.